1. Field of the Invention
The present invention relates to a display apparatus suitably used for displaying a stereoscopic image by disposing a plurality of display devices at a predetermined interval on a view line of a viewer and superimposing images generated by these display devices, and further relates to a display device used as a unit for constructing the display apparatus.
2. Description of the Related Art
Heretofore, various types of display apparatuses allowing a stereoscopic display are presented or put into practical use. For example, a Liquid Crystal Shutter (hereinafter referred to as “LCS”) glasses system or the like is well known as an electrically rewritable display apparatus allowing a stereoscopic display. In this LCS glasses system, an object is shot from different directions with one or more cameras, and the obtained image data, including the parallax information, are synthesized to a picture signal, that is supplied to the display apparatus where it is displayed. While the viewer wears the LCS glasses, typically an LCS for right eye is in a light transmissive state, and an LCS for left eye is in a light blockage state during an odd field. On the other hand, the LCS for left eye is in the light transmissive state, the LCS for right eye is in the light blockage state during an even field. For this, an image for right eye is displayed in the odd field, while an image for left eye is displayed in the even field, and thereby these images for right or left eye including each parallax are viewed through the right or left eye respectively, resulting in a stereoscopic image.
On the other hand, there is a display apparatus allowing a stereoscopic display, by disposing a plurality of display members with a predetermined distance from each other on the view line of the viewer, and superimposing images generated by each display member, although this stereoscopic image is rather discrete in a depth direction. Furthermore, there is an improvement of the display apparatus, in which the luminance or brightness of image displayed on each display members is modulated, in order to improve the discrete image, and thereby the viewer feels an improved stereoscopic illusion as if the object is between two discrete images. For example, there is an intensity modulation type (i.e., a brightness modulation type or a luminescence modulation type) of display apparatus allowing that a semi-transparent object or an object in backward become transparent by superimposing the object images generated by said a plurality of display members using a plurality of half mirrors (e.g. Japanese Patent Application Laid-Open No. 2000-115812).
Nevertheless, in the display apparatus having a plurality of display members disposed with a predetermined distance from each other on the view line of the viewer, there is a technical problem that an image to be displayed on one display member is apt to be reflected on other display member(s), and thereby the viewer fails to view an appropriate image. For example, a light emitted from one display member having a light transmissive property propagates not only in a direction to the viewer but also in a direction opposite to the viewer, due to the light transmissive property of the display member. In this case, the light emitted from one display member is reflected on other display member(s) disposed toward behind the former display member as seen from the viewer, and thereby the viewer views the wrong image different from the image to be viewed. That is, since it is difficult or impossible to display a stereoscopic image in an appropriate state, there is a technical problem of difficulty in displaying a stereoscopic image, in spite of employing any type of the intensity modulation display apparatus.
Additionally, the light is wastefully consumed for this reflection of the light, and thereby there is a technical problem of low efficiency in utilizing the light for the display.